CATTR instruction (z/OS® and CMS)

Edit online
The CATTR instruction establishes a program object external class name, and assigns binder attributes for the class. This instruction is valid only when you specify the GOFF or XOBJECT assembler option.
Read syntax diagramSkip visual syntax diagramclass_nameCATTR, attribute
class_name
Is a valid program object external class name. The class name must follow the rules for naming external symbols, except that:
  • Class names are restricted to a maximum of 16 characters
  • Class names with an underscore (_) in the second character are reserved for IBM® use; for example B_TEXT. If you use a class name of this format, it might conflict with an IBM-defined binder class.
attribute
Is one or more binder attributes that are assigned to the text in this class:
ALIGN(n)
Aligns the text on a 2n boundary. n is an integer with value 0, 1, 2, 3, 4, or 12. If not specified, then the SECTALGN option value (8 is the default, corresponding to ALIGN(3)) is used (see the section SECTALGN in the HLASM Programmer's Guide for more information).
Note: Execution-time support of the desired alignment depends on its being respected by other operating system components such as linkers and loaders.
DEFLOAD
The text is not loaded when the program object is brought into storage, but is probably requested, and therefore partially loaded, for fast access.
EXECUTABLE
The text can be branched to or executed—it is instructions, not data.
FILL(nnn)
The fill character to be attached to this part. The value must be specified as an unsigned decimal number and must lie between 0 and 255. An invalid priority is ignored and the diagnostic message 'ASMA062E Illegal operand format xxxxxx' is issued.
The FILL attribute can be specified on the first CATTR instruction for the part. If the FILL attribute is specified on the second or subsequent CATTR instruction for the part, the FILL attribute is ignored and the diagnostic message ASMA191W is issued.
The FILL attribute is ignored if there is no PART attribute on the CATTR instruction and the diagnostic message 'ASMA062E Illegal operand format xxxxxx' is issued.
MOVABLE
The text can be moved, and is reenterable (that is, it is free of location-dependent data such as address constants, and executes normally if moved to a properly aligned boundary).
NOLOAD
The text for this class is not loaded when the program object is brought into storage. An external dummy section is an example of a class which is defined in the source program but not loaded.
NOTEXECUTABLE
The text cannot be branched to or executed (that is, it is data, not instructions).
NOTREUS
The text is marked not reusable.
PART(part-name)
Identifies or continues the part with the name part-name. The part-name can be up to 63 characters in length. An invalid part-name is ignored and diagnostic message 'ASMA062E Illegal operand format xxxxxx' is issued.

Binding attributes assigned to the class are also assigned to the part. Both the class and the part are assigned to Name Space 3 and are assigned the merge attribute.

Text within a part cannot contain an entry point. If an entry point is found within the part it is ignored and diagnostic message 'ASMA048E Entry error - xxxxxxxx' is issued.

The following rules apply to the validation of the PART attribute on the CATTR instruction:
  • If the PART attribute has not been specified on the first CATTR statement for the class, but is specified on subsequent CATTR statements for the class, the attribute is ignored and diagnostic message ASMA191W is issued.
  • If the PART attribute has been specified on the first CATTR statement for the class, but is not specified on subsequent CATTR statements for the class, the diagnostic message ASMA155S is issued.
  • Multiple parts can be defined within a class.
PRIORITY(nnnnn)
The binding priority to be attached to this part. The value must be specified as an unsigned decimal number and must lie between 0 and 231-1. An invalid priority is ignored and diagnostic message 'ASMA062E Illegal operand format xxxxxx' is issued.

The PRIORITY attribute can be specified on the first CATTR instruction for the part. If the PRIORITY attribute is specified on second or subsequent CATTR instructions for the part it is ignored and the diagnostic message ASMA191W is issued.

The PRIORITY attribute is ignored if there is no PART attribute on the CATTR instruction and the diagnostic message 'ASMA062E Illegal operand format xxxxxx' is issued.

READONLY
The text is storage-protected.
REFR
The text is marked refreshable.
REMOVABLE
The content of this class can be discarded from the program object at bind time if the user specifies an appropriate binder option. This might help reduce the size of the program object.
RENT
The text is marked reenterable.
REUS
The text is marked reusable.
RMODE(24)
The text has a residence mode of 24.
RMODE(31)
The text has a residence mode of 31.
RMODE(64)
The text has a residence mode of 64.
RMODE(ANY)
The text can be placed in any addressable storage.

These attributes are accepted by the assembler and encoded in the GOFF object file, but some are not processed by the binder.

Refer to the z/OS MVS Program Management: User's Guide and Reference, SA22-7643 for details about the binder attributes.

Default Attributes: When you do not specify attributes on the CATTR instruction the defaults are: ALIGN(3),EXECUTABLE,NOTREUS,RMODE(24) The LOAD attribute is the default if DEFLOAD or NOLOAD are not specified.

Where to Use the CATTR Instruction: Use the CATTR instruction anywhere in a source module after any ICTL or *PROCESS statements. The CATTR instruction must be preceded by a START, CSECT, or RSECT statement, otherwise the assembler issues diagnostic message ASMA190E.

A section can contain any number of classes. Any machine language instructions or data appearing after a CATTR instruction are components of the element defined by the section and class names. An element is a separately relocatable component of the resulting program object, and is typically bound with other elements having the same attributes.

If several CATTR instructions within a source module have the same class name, the first occurrence establishes the class and its attributes, and the rest indicate the continuation of the text for the class. If you specify attributes on subsequent CATTR instructions having the same class name as a previous CATTR instruction, the assembler ignores the attributes and issues diagnostic message ASMA191W.

If you specify conflicting attributes on the same instruction, the assembler uses the last one specified. In the following example, the assembler uses RMODE(ANY): 
MYCLASS  CATTR RMODE(24),RMODE(ANY)

Syntax Checking Only: If you code a CATTR instruction but do not specify the GOFF or XOBJECT option, the assembler checks the syntax of the instruction statement and does not process the attributes.